<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .bg_color{
            background-color: #eb4d4b;
        }
        .mb10{
            margin-bottom: 10px;
        }
        .mb20{
            margin-bottom:20px;
        }
        .success{
            border: solid 1px green;
        }
        .error{
            border: solid 1px red;
        }
    </style>
</head>
<body>
    <!---多类样式声明--->
    <div class="success mb10 bg_color">操作成功</div>
    <div class="error mb20 bg_color">表单错误</div>
    <div class="error mb20 bg_color">表单错误</div>
</body>
</html>